Geoscience Reference
In-Depth Information
on fi sh populations when deciding whether to build or replace dams. In
considering dam projects in the state of Washington, one question was
the value of salmon, steelhead, and other migratory fi sh populations.
We could estimate the market value of the fi sh catch in the supermar-
kets, but that would leave out the nonuse values.
A study by Layton, Brown, and Plummer can illustrate how the
CVM can be used to estimate the value to local households of changes
in fi sh populations under different scenarios. Specifi cally, the authors
conducted a contingent value survey to estimate the value of returning
the fi sh populations to current levels in 20 years rather than continuing
to allow the fi sh populations to decline. The authors estimated that on
average, Washington households were willing to pay $736 per year for
affected, this comes to a total of $3.7 billion a year.
While CVM techniques have been applied in many areas, to date
they have not been used on the scale and scope necessary for estimating
the impacts of global warming. There are formidable, even insuperable,
obstacles to undertaking a complete appraisal of the impact of climate
change on the value of lost species and damaged ecosystems. One diffi -
culty is that scientists have great diffi culty in specifying the changes that
need valuation. We saw above how disparate are the estimates of the
number of species that would be lost, and the timing of losses would add
another complication. A second diffi culty is the sheer scale of the task. It
involves undertaking evaluations not just for migratory fi sh in the state
of Washington but for species and ecosystems around the world, in re-
mote corners where there are very scant measurements to begin with.
Additionally, the use of CVM has been highly controversial in eco-
nomics and is not universally accepted. Some argue that “some number
is better than no number.” Others argue that in the absence of reliable
methods, “no number is better than a fl aky number.” Many years of
debate and further research have not produced a consensus on this ap-
proach.
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Some experts argue that the responses are unreliable given the in-
herent diffi culty in thinking about the relevant questions. People are
asked about a counterfactual situation that they may not understand.
